The preset invention relates to a picture recording device camera system.
German Published Patent Application No. 195 45 484 describes a picture recording device. The picture recording device is one physical unit which is disadvantageous in many applications of a picture recording device in which a screen is already present in the form of a cathode ray tube or an LCD display.
An object of the present invention is to design a picture recording device in such a way that it can be used advantageously in front of a screen.
The object is accomplished by the present invention by using a picture recording device having at least one photodetector per picture element to be recorded, in front of which one focusing element for each element of the picture to be recorded is arranged on the photodetector, with the picture recording device being fabricated as a thin sheet which, on the side facing away from the picture to be recorded, has further focusing elements arranged in such a way that the light emitted from a screen having the picture recording device mounted thereon is focused in a plane inside or directly in front of the picture recording device. This sheet should preferably be flexible.
The picture recording device based on the present invention has an advantage that the focusing elements (focusing lenses) required for picture recording do not disturb the viewing of the picture generated on the screen.
An advantageous design of the picture recording device according to the present invention is such that the light emitted from the screen is focused in the plane of the focusing elements. With this design, the light emitted from the screen is in no way affected by the lenses needed for picture recording. However, since the screen is located behind a glass pane, which may possibly be of considerable thickness compared with the picture recording device, it may be expedient if further focusing elements have a larger area than the focusing elements, i.e., that the array formed by the further focusing elements is much coarser. As a result, each of the further focusing elements covers a larger radiation angle than would be the case with an area corresponding to the focusing elements.
Depending on the prevailing conditions, the device may be so designed that the further focusing elements are formed by one focusing lens each or that the further focusing elements are formed by two focusing lenses which are spaced apart from one another. This embodiment is especially suited for screens having a thick glass pane.
Another embodiment also adapted to such conditions is designed in such a manner that each further focusing element is assigned in the same axis to one photodetector and one focusing element, where the light emitted from the screen is preferably focused in a plane disposed between the photodetector and the plane of the focusing elements.
In a further embodiment of the picture recording device according to the present invention, the photodetectors are prevented from being exposed to the light emitted from the screen by placing an opaque layer on the side of the photodetectors facing away from the picture to be recorded, so that the light emitted from the screen does not impair the photodetectors.
Another embodiment may be used for recording color pictures and is characterized in that color filters, which permit a separation of the different colors of the light, are placed in front of the photodetectors.
An additional embodiment of the picture recording device according to the present invention provides that light emitted from the screen be reflected by an object approaching the picture recording device, to at least one of the photodetectors, and that information be obtained indicating which of the photodetectors receive reflected light. In this way, a picture recording device according to the present invention can be used together with a screen as an input unit, e.g., for a computer, where it suffices to point with one""s finger or a suitable object at predefined fields (see German published Patent Application No. 195 45 484).